Method of transforming a crop waste into a solid fuel and a solid fuel made by the method

ABSTRACT

A method of transforming a crop waste into a solid fuel includes the steps of dehydrating the crop waste such as rice husks, rice stalks, hays, or plant stems to have a water content of from 18% to 30% by weight, smashing and stirring; adding an additive having clay ingredient, and compressing at a temperature of 150 to 210 degrees Celsius and a pressure of 300 Psi/cm 2  to 600 Psi/cm 2  to form a block-shaped fuel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of transforming a crop waste into a solid fuel and a solid fuel made by the method, and more particularly, to a method comprising the steps of dehydrating the crop waste such as rice husks, rice stalks, hays or plant stems; smashing and stirring; adding an additive; and compressing the crop waste to form a solid fuel.

2. Description of the Related Prior Art

In accordance with the information provided by Council of Agriculture, Executive Yuan, Taiwan, there are over 6 million tons of crop waste each year. In the past, the crop waste was burned and buried on the spot as fertilizer. Since the energy is running short worldwide now, researchers are studying how to change the crop waste to a better way, such as energy. An example of which is to transform rice husk, bagasse, awn into ethanol fuel, however, this technique is complicated and requires electricity, air, water and steam in process. Thus the cost is high.

According to documents, a conventional solid fuel is formed by smashing the crop waste, separating, dehydrating, mixing with an additive and forming. The crop waste may be rice husk, bagasse, the pod of any legume or corn stalk. But the materials are too humid to be burned completely and to be stored. If the crop waste has higher water content, the burning of the crop waste will produce mass steam which will erode the mechanism of a boiler. If the crop waste has lower water content, it will be difficult to form a solid fuel which may break into pieces during transportation. A traditional additive uses organic chemistry macromolecule polymer such as wax or polythene for providing a better binding effect. But this additive will produce poison gas which pollutes the air and damages human being.

SUMMARY OF THE INVENTION

The present invention is to improve the above-mentioned shortcomings.

According to a first aspect of the present invention, there is provided a method of transforming a crop waste into a solid fuel, comprising the followings steps:

-   -   A. dehydrating: the crop waste being dehydrated to have a water         content of from 18% to 30% by weight;     -   B. smashing and stirring: smashing the crop waste into small         particles or powders and stirring evenly;     -   C. adding additive: adding an additive having clay into the crop         waste; and     -   D. compressing: compressing the crop waste into a block-shaped         fuel at a temperature of from 150° C. to 210° C. and a pressure         of from 300 Psi/cm² to 600 Psi/cm².

Preferably, the dehydrating in step A is done by exposure to sunlight or machine processing.

Preferably, the crop waste is dehydrated to have a water content of 25% by weight.

Preferably, the compressing in step D is formed by a mold and processed with heat and instant cooling.

Preferably, the block-shaped fuel is treated with carbonization.

According to a second aspect of the present invention, there is provided a solid fuel made by the method of transforming a crop waste into a solid fuel.

Preferably, the crop waste is selected from one of rice husk, rice stalk, hay and plant stem.

Preferably, the clay is aluminosilicate.

The present invention produces a high density and high heat valve solid fuel with a natural organic additive which will not produce any poison gas or substance. Each season, farmers plant different crops, the procedures may be varied in accordance with the crops.

It is the primary objective of the present invention to provide a method of transforming a crop waste into a solid fuel, which transforms the crop waste into a valuable solid fuel to improve the environment and to increase farmer's income.

It is another objective of the present invention to provide a method of transforming a crop waste into a solid fuel, which provides a solid fuel having higher heat valve per unit volume, enough burning temperature, less smoke, and lower sulfur which produces less sulfur dioxide during burning, decreasing the harmful gas which produces acid rain to pollute the environment.

It is a further objective of the present invention to provide a method of transforming a crop waste into a solid fuel, which provides a solid fuel treated with carbonization process to replace a traditional charcoal, which contains less sulfur for protecting the environment, has a smaller size, and is safe in use and convenient to carry.

It is a further objective of the present invention to provide a method of transforming a crop waste into a solid fuel, which uses natural organic clay as an additive. The main ingredient of the clay is aluminosilicate in small particles (<2 μm) which have strong capillary attraction to bind the dried crop waste. The aluminosilicate is stable chemical compound and will not produce odor or poison substances to pollute the environment during burning.

BRIEF DESCRTIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of the present invention, and

FIG. 2 is a schematic view of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIGS. 1 and 2, a method for transforming a crop waste into a solid fuel of the present invention comprises the following steps of:

-   -   A. dehydrating: a crop waste (1) is dehydrated to have a water         content of from 18% to 30% by weight. The crop waste (1) may be         rice husks, rice stalks, hays, or plant stems. Dehydration may         be obtained by means of exposure to sunlight or machine         processing. The reduction of the crop waste water content         facilitates burning and reduces odor dispersal. The process may         be varied as certain crop waste products are available only         seasonally. The preferred crop waste is dehydrated to have a         water content of 25% by weight;     -   B. smashing and stirring: the dehydrated crop waste (1) is         smashed into small particles or powders (2) and then stirred         evenly;     -   C. adding additive: adding an additive such as clay (3) into the         smashed crop waste (1). The clay (3) is formed with natural         substances in small particles which have strong capillary         attraction to bind the dried crop waste (1). The additive used         in the present invention replaces a traditional additive which         uses organic chemistry macromolecule polymer. The main         ingredient of the clay (3) is aluminosilicate which is stable         chemical compound and will not produce odor or poison substances         to pollute the environment during burning; and     -   D. compressing: by compressing the crop waste (1) added with the         clay (3) to form a solid fuel (5). The compressing is at a         temperature of from 150° C. to 210° C. and a pressure of from         300 Psi/cm² to 600 Psi/cm². The temperature and pressure may be         varied, depending upon different seasonal crop waste (1). Step A         will dry the crop waste (1) to have a water content of 18% to         30% by weight. When the crop waste (1) has higher water content,         the temperature and pressure of the compressing will be raised.         The clay (3) in step C has a strong blinding character to         facilitate the compressing. The compressing is done by means of         a mold (4), and then to be dried by hot wind and instant         cooling. The hot wind dries the crop waste (1) to facilitate         forming. The instant cooling makes the crop waste (1) contract         for enhancing its degree of polymerization and density and         increasing heat valve per unit volume.     -   The solid fuel (5) is made by the aforesaid method of         transforming a crop waste into a solid fuel.

The solid fuel (5) has enough burning temperature in use and has a very limited smoke during burning. Therefore, it may be used to light a boiler instead of heavy oil. The solid fuel (5) has lower sulfur which produces less sulfur dioxide during burning, decreasing the harmful gas which produces acid rain to pollute the environment. The use of the crop waste (1) corresponds to environment protection and may improve the farmer's living.

The solid fuel (5) may be treated with carbonization process to replace a traditional charcoal, which contains less sulfur for protecting the environment. The present invention is safe in use. In addition, the ashes of the present invention after burning may be treated as fertilizers. 

1. A method of transforming a crop waste into a solid fuel, comprising the following steps of: A. dehydrating: the crop waste being dehydrated to have a water content of from 18% to 30% by weight; B. smashing and stirring: smashing the crop waste into small particles or powders and stirring evenly; C. adding additive: adding an additive having clay into the crop waste; and D. compressing: compressing the crop waste into a block-shaped fuel at a temperature of from 150° C. to 210° C. and a pressure of from 300 Psi/cm² to 600 Psi/cm².
 2. The method of transforming a crop waste into a solid fuel, as claimed in claim 1, wherein the dehydrating in step A is done by exposure to sunlight or machine processing.
 3. The method of transforming a crop waste into a solid fuel, as claimed in claim 1, wherein the crop waste is dehydrated to have a water content of 25% by weight.
 4. The method of transforming a crop waste into a solid fuel, as claimed in claim 1, wherein the compressing in step D is formed by a mold and processed with heat and instant cooling.
 5. The method of transforming a crop waste into a solid fuel, as claimed in claim 1, wherein the block-shaped fuel is treated with carbonization.
 6. A solid fuel made by the method of transforming a crop waste into a solid fuel as claimed in claim
 1. 7. The solid fuel, as claimed in claim 6, wherein the crop waste is selected from one of rice husk, rice stalk, hay and plant stem.
 8. The solid fuel, as claimed in claim 6, wherein the clay is aluminosilicate. 